package 奇数位丢弃;

import java.util.ArrayList;
import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while (in.hasNext()) {
            int n = in.nextInt();
            int ret = 1;//2^0
            while (ret - 1 <= n) {
                ret *= 2;
            }
            System.out.println(ret / 2 - 1);
        }
    }
}